“Rain is expected, but the movie will continue no matter what,” says the announcer at the Grant Park Outdoor Film Festival. Tonight screens “The Blues Brothers,” and half of Chicago jostles to nab choice lawn spots. Blankets cover Butler Field like a second skin. Meanwhile, somewhere over suburbia a thunderstorm prepares for battle, about to test the crowd’s devotion to their beloved hometown film.

The skies are clear at first, but as the “mission from God” commences, ominous clouds sweep in from the southeast. Heedless couples groove to John Lee Hooker while silent heat lightning flickers over Pilsen, and a few fat drops of rain fall. A crack of lightning lances the sky behind the screen. Elwood and Joliet Jake break into “Sweet Home Chicago” and the downpour arrives. Some audience members stare at the lightning-struck sky, eye the metal skeletons of the half-constructed Lollapalooza stages and skedaddle. But the rest dance, strip off shirts and open their arms to the heavens. They sing out the lyrics to their city’s quintessential anthem, “Hidehay! Baby don’t you wanna go!”

The crowd can’t hear the audio anymore, but it doesn’t matter; they know the dialogue by heart. In unison, they bellow up at the raging thunderhead. “It’s 206 miles to Chicago!” thousands of sodden Chicagoans shout as one, fists outstretched as if punching the sky. “We’ve got a full tank of gas, half a pack of cigarettes, it’s dark and WE’RE WEARING SUNGLASSES… HIT IT!” (Laura Hawbaker)